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Front Collision TESLA P85. Repair and Troubleshooting Help Needed.

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#181
Test results:
1. Dcdc signal plug disconnected, pin 5 and 6 are connected together separately from the plug. Cover from HV connectors removed. When 12V* battery was connected i saw 140-180V on each of two HV wires. However NO Charge to the 12V battery.
2. When I put pin 5 and 6 back in the connected and pin 1 and 2 disconnected from dcdc, i dont get any voltage on HV. The voltage on pin 4 at this time is around 120mV which is very low. So I apply 11.3V to the pin 4 with 12V battery connected i still dont get any voltage on HV Wires. This pretty much simulates the test that Ingineer performed, but it fails on my car when installed. However I dobt hear contacts closed when pin 1 and 2 are out.
3. After installing all pins back together the HV contractors never closed and NO Voltage on pin 4 either.
I have no idea what went wrong now.
 
#182
140-180V is odd. I wonder if there is a poor connection somewhere. I would expect 300-400V or nearly zero volts. To get somewhere in the middle is unusual, to say the least.

Has the DC-DC converter been opened up yet by anyone? It may be possible to bypass the CANbus test by finding the controller chip and toggling the enable line directly -- assuming it's not one of the newer digitally-controlled power supplies. This would at least allow the DC-DC to be checked.
 
#184
When I did test 1, the Pin 4 had its own 11.3V, possibly coming from a 12V battery, so I didnt apply any voltage on it. When I did test 2, then pin 4 didnt have any voltage so I used battery charger, applying 11.3V on it. Now thinking about it, it could overload the signal on pin 4 and maybe burned the fuse or something. Because now my charge port is RED and Battery Pack contacts open, so NO High Voltage from the Battery Pack.
 
#185
I'm back from my 4th of July vacation and can assist some more.

Perform the test again, with the HV wires connected, but the cover removed. Do the same jumper of pins 5 and 6, and only provide a connection to pin 4 from the connector (enable) leaving off CAN (5 & 6 as well). Do not measure to ground on HV, it is isolated.

12v battery fully charged. Turn on the car. The contactors should close, if they don't something else is wrong and there's no point in testing any farther.

So now were going to measure:

1. ACROSS the 2 HV DC wires with meter on DC range > 400. Cannot measure HV to ground as it is isolated.
2. From pin 4 to ground.
3. From large red bolt terminal to ground.
4. from battery positive to ground.

Report these here.
Then measure pin 4 compared to ground, and fina
 
#186
When I did test with removed pin 5 & 6, contact were closing after 12V battery was connected. However when I removed pin 1 & 2 for CAN, the contact were not closing and no power was going from the Battery Pack to DC-DC. Also, after I put voltage on pin 4 from battery charger (11.3V, not sure how many amps, probably like 10 , thats what it says on the charger) the car never closed the contacts on the the battery pack and now its not providing any voltage on pin 4 like it did before. Car is not running and charge port is Red now.
 
#188
Yauheni said:
I just did few more test again and no luck so far. The contacts dont close after i performed few tests a few days ago. So No power on HV wires and no power on pin 4. Battery is 12.63V as well as voltage on dcdc converter is the same 12.63V.
Click to expand...

Try these steps:

Disconnect 12V battery
Disconnect DCDC signal harness
Make sure High Voltage loop is closed (Pins 5 & 6; Yellow with Dark Blue & Yellow with Dark Gray) short them on the signal harness (not the DCDC connector)
Wait long enough (like, go to work)
Once you return from work and had dinner, child went to bed goto next step
Connect 12V battery
Check if contactor now closes
If its still no-go, red ring on the charge port, you're partially screwed and got 12V on the signal pin going in the battery on the BMS board... argh.
If so, check with @wk057 if he has any BMS board left or can help. This thread might give you an idea of what you need to do...
 
#189
Ok. So its been over 24 hrs after i worked on the car. After making a huge mistake and putting almost 12V into BMS instead of dcdc the car stopped closing contacts on battery pack.
I was 99% sure that I fried BMS inside of battery pack.
Now, i disconnected pin 5 and 6 and shorted it manually, while pine 1 and 2 was inserted into DCDC. Pin 4 was connected to 5.5V source and HV were connected like supposed to be, and covered with cup. After connecting 12V battery i heard battery pack fontacts closed and charge port is ready for charging now. Huh Thanks God, seems like BMS is still good.
Now i checked voltage coming from BMW on pin 4 wire harness and it is 11.3V. However DCDC is not charging 12V battery. Same story.

Thanks for your help folks.
 
#192
Excellent news! I was hoping you didn't damage the BMS. It sounds fine.

Disconnect the 12V system and make sure the contactors open. Open the HVJB cover which is under the rear seat cushion right in the middle, and find the big fuse in there. I think it's 100A. See if it's blown by ohming it out. If it is, check the wiring from the fuse carefully to make sure it's isolated from everything, including doing resistance testing on it. If it all checks good, it was probably when the accident occurred the old DC-DC got crushed and blew it. You'll need to replace that fuse! (The fuse is protecting the wiring running up front)

Here's a picture of the inside of the HVJB:
hvjb-sm.jpg
 
#194
I thought you were seeing HV before on the DC-DC line? Not sure how you could have blown a fuse on the HV side since, but Ingineer's explanation would make sense if you've never seen HV up front. I thought you had mentioned before that your A/C and heat worked? Same fuse.

If the contactors are closing you should have HV across HV+/HV- inside the HVJB in the back for sure. There is no fusing between the pack output and that junction box, only the main pack fuse.... and you'd have had to do something spectacular to pop that one (over 630A @ HV). The rear HVJB does has a HVIL microswitch on the lid somewhere, so if you plan on testing for voltage with it open keep that in mind... and wear HV PPE.

Are you seeing voltage from the BMS on pin 4 again?
 
#198
I just opened up HVJB and checked the fuses, 100amp fuse IS blown, the other 2 are fine. Checked resistance on HV an its around 1ohm on both of them.
I have 12v battery is disconnected, so there is NO power in HVJB??? Or there is??? It seams like i dont see power at all.
 
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